Coolant delivery matrix

ABSTRACT

An internal combustion engine includes a cooling system having a coolant delivery matrix, such as for providing a two phase (vapour) cooling system for the engine. The coolant delivery matrix is configured for location in a cylinder block of an engine housing of the internal combustion engine. The coolant delivery matrix includes a manifold and a plurality of pipes extending from the manifold. The coolant delivery matrix is further configured to locate around at least one cylinder in the cylinder block, and each of the plurality of pipes has at least one aperture being directed to spray liquid coolant at a wall of the at least one cylinder.

TECHNICAL FIELD

The present disclosure relates to improvements in cooling systems for internal combustion engines, and in particular to a matrix suitable for providing a two phase (vapour) cooling system for an internal combustion engine.

BACKGROUND

Internal combustion engines have at least one cylinder in which a piston is reciprocally moveable. The piston is drivably connected to a crankshaft via a connecting rod. The cylinder block of an internal combustion engine may be a unit comprising several cylinders defined by cylinder walls. A cylinder head may be located on top of the cylinder block, where it forms the top of the combustion chamber. One end of the combustion chamber typically has at least one intake port and an associated, intake valve and at least one exhaust port with an associated exhaust valve. Generally, the intake and exhaust ports are provided in a cylinder head.

A four stroke internal combustion engine may have an intake stroke in which the intake valve may open, an intake port so that the combustion chamber is brought into fluid connection with an air intake system. During the intake stroke, the piston in the combustion chamber may move away from the cylinder head and thus, fresh combustion air may be sucked into the combustion chamber. Subsequently, the piston reverses its direction and moves towards the cylinder head for making a compression stroke.

During the compression stroke the intake valve and the exhaust valve are closed. At a certain moment during the compression stroke fuel is injected into the combustion chamber. Next, the fuel/air-mixture in the combustion chamber combusts and the piston motion is reversed and the power stroke takes place. During this power stroke, the combustion energy produced may be converted into kinetic energy of increased piston movement which is transferred to rotation of the crankshaft. After the power stroke, the piston movement reverses its direction and moves towards the cylinder head for making an exhaust stroke. During the exhaust stroke the intake valves are closed and the exhaust valves are opened.

Engine cooling is necessary to avoid high temperature damage to engine materials and lubricants. Internal combustion engines operate at temperatures higher than the melting temperature of engine materials, and hot enough to set fire to lubricants. Engine cooling removes energy fast enough to keep temperatures low so that the engine is not damaged.

In many conventional cooling systems a liquid coolant is pumped into a coolant jacket surrounding the cylinder head where the liquid coolant becomes heated. As the heated coolant leaves the engine, it is passed through a heat exchanger, such as a radiator equipped with a fan, which cools the coolant. The cooled coolant is then recirculated back into the engine. The coolant jacket is usually cast into the cylinder block, so that the coolant passages are integral with the cylinder block which creates complexities in design and an associated manufacturing cost.

In recent years the developments in internal combustion engine technology have been focussed on reducing fuel consumption and exhaust emissions. However such developments may lead to a decrease in the thermal efficiency of the engine, A number of improved cooling and exhaust heat recovery systems have been proposed to reduce cooling loss and provide additional power from waste heat. Some such systems use two (or dual) phase cooling (also known as vapour cooling), examples of which are described in US-B-5199397 and EP-A-0579553.

In such a two phase cooling system the coolant is present in the engine in two phases, namely the liquid and vapour phases. The coolant is in its liquid phase during engine warm up and is heated by the engine to its boiling point, At this point the coolant generates vapour and the resulting coolant liquid and coolant vapour are separated with the vapour being directed to a condenser to be condensed before being returned in liquid phase to the engine.

It has also become apparent that the separate phases can be used in a manner which optimises the thermal energy recovery and that the coolant can be returned to the engine as a mixture of both phases.

Such cooling systems may offer more rapid engine warm up, a reduction in the coolant mass flow, and therefore a reduction in the coolant system and radiator size, a reduction in coolant pumping power and an increase in the amount of waste energy available for thermal energy recovery systems.

The present disclosure is directed to further improvements in the existing technology.

SUMMARY

The present disclosure therefore provides for a coolant delivery matrix configured for location in the cylinder block of an engine housing, said matrix comprising a manifold and a plurality of pipes extending from said manifold, said matrix being configured to locate around at least one cylinder in the cylinder block, said pipes having at least one aperture being directed to spray liquid coolant at a well of the at least one cylinder.

The present disclosure further provides for a cooling system for an internal combustion engine, said cooling system comprising the aforesaid coolant delivery matrix; a supply pump fluidly connected to supply liquid coolant under pressure to the coolant delivery matrix; an extraction pump adapted to extract vaporised coolant from the engine housing; and a condenser fluidly connected upstream to the extraction pump and downstream to the supply pump.

The present disclosure further provides for an internal combustion engine comprising a housing provided with a plurality of cylinders located in a cylinder block and a cylinder head attached to the cylinder block, and the aforesaid cooling system, wherein the coolant delivery matrix is located in the cylinder block and the apertures are directed to spray liquid coolant at parts of the cylinder block and cylinder head.

The present disclosure further provides for a method of cooling the aforesaid internal combustion engine, said method comprising the steps of providing liquid coolant to the coolant delivery matrix under pressure; spraying a plurality of jets of liquid coolant onto selected parts of the engine; extracting vaporised coolant from the engine block; condensing the vaporised coolant into liquid coolant; and recirculating the condensed liquid coolant to the coolant delivery matrix.

The present disclosure further provides for a method of manufacturing the aforesaid internal combustion engine, comprising the steps of manufacturing the coolant delivery matrix; manufacturing the cylinder block and cylinder; positioning the coolant delivery matrix within the cylinder block so that the apertures are directed to spray liquid coolant at parts of the cylinder block and cylinder head; and attaching the cylinder head to the cylinder block.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic of an exemplary embodiment of an internal combustion engine;

FIG. 2 is a schematic of a cooling system for an internal combustion engine such as that illustrated in FIG. 1;

FIG. 3 is a perspective view of the cylinder block of the internal combustion engine of FIG. 1 with a front section of the cylinder block wall and the cylinder head removed to show the coolant delivery matrix;

FIG. 4 is a plan view of the cylinder block of FIG. 3 with the cylinder head removed;

FIG. 5 is a front cross sectional elevation through a pipe of the coolant delivery matrix of FIG. 3;

FIG. 6 is a front cross sectional elevation of the connection of the coolant delivery matrix to the cylinder block;

FIG. 7 is a plan view showing the feeds into the cylinder head, from the underlying cylinder block illustrating target points for the coolant; and

FIG. 8 is a front cross sectional elevation through an upper section of the cylinder block and cylinder head.

DETAILED DESCRIPTION

The present disclosure is directed towards a matrix suitable for providing a two phase (vapour) cooling system for an internal combustion engine, in which a liquid coolant is sprayed towards hot spots in the cylinder block and cylinder head. The liquid coolant vaporises on contact with the hot engine parts and the resulting coolant vapour is extracted from the cylinder block and cylinder head, for condensing and recycling. The matrix may be manufactured separately from the cylinder block and head of the engine and inserted into the engine block during construction of the engine.

Referring to FIG. 1, there is shown a simplified schematic illustration of an exemplary internal combustion engine 10. The engine 10 typically comprises an engine housing 11 in which a plurality of cylinders 12 are located, in each of which is mounted a piston 13. The piston 13 is able to move in a reciprocating manner in the cylinders 12. Fuel injectors 14 are located so as to extend at least partially into each of cylinders 12 and are operable to inject fuel directly into the cylinders 12 ahead of the pistons 13. As the pistons 13 move towards the injectors 14 they compress the fuel, which ignites and forces the piston 13 back in the opposite direction. Each piston 13 may be coupled to a crankshaft 15, by means of a piston rod 15, to enable rotation of crankshaft 15 as the pistons 13 reciprocate in the cylinders 12. The fuel, may be supplied by a high pressure pump 17, which supplies pressurised fuel to a pressurised fuel source, such as a common rail 18, which in turn is fluidly connected to supply fuel to the fuel injectors 14.

Referring also to FIG. 2, air may be supplied to the engine 10 by means of an air intake conduit 19. The air intake conduit 19 may be connected to an intake manifold 20 which distributes the air to the cylinders 12, via intake ports (not shown), for the combustion process. The engine 10 may also include one or more exhaust passages 21 extending from exhaust ports (not shown) in the engine housing 11 for conducting the exhaust away from the cylinders 12. The exhaust passages 21 may supply exhaust gas via an exhaust conduit 22 to a high pressure turbocharger 23. The exhaust conduit 22, in which the high pressure turbocharger 23 is located, may be connected to the exhaust system to provide the exhaust gas flow.

FIG. 2 is a schematic representation of one embodiment of a cooling system 24 for an internal combustion engine 10 such as that illustrated in FIG. 1. It is to be understood that the cooling system 24 is suitable for use with a variety of other designs of internal combustion engine, other than the one illustrated herein.

Referring to FIGS. 3 to 8, the engine 10 is cooled by means of a coolant 41 which, has a liquid form at room temperature. One suitable coolant 41 may be substantially water based, possibly with some anti-corrosive additives making up a small proportion of the coolant 41. The coolant 41 is supplied, to the cylinder block 25 in which the cylinders 12 are located. A cylinder head 31 may be attached to the cylinder block 25 by a plurality of bolts screwed into bosses 26 in the cylinder block 25 (see FIGS. 3 and 4). The cylinder block 25 may be of an open deck design with a head gasket 32 located between the cylinder head 31 and cylinder block 25 to seal the joint therebetween. In an open deck design the cylinders 12 are separated from the outer wall of the cylinder block 25. The cylinder head 31 and cylinder block 25 may comprise three decks, namely a top deck (not shown), a mid-deck 33 and a fire deck 34 (see FIG. 8). The fire deck 34 generally overlies the cylinder block 25.

The fuel injectors 14 may pass through apertures 45,46 in the fire deck 34 of the cylinder head 31. Where the fuel injectors 14 pass through the fire deck 34, a seal may be created between the fuel injector 14 and the apertures 46. However where the fuel injectors 14 pass through the mid-deck 33, a gap is left between the fuel injector 14 and the mid-deck 33.

The coolant 41 is distributed within the cylinder block 25 by a coolant delivery matrix 27. The coolant delivery matrix 27 is designed to direct jets of liquid coolant 41 under pressure at engine hot spots, such as the walls of the cylinders 12 and/or areas of the fire deck 34 of the cylinder head 31. The matrix 27 is formed from a manifold 28, which may encircle the cylinders 12 inside the cylinder block 25, and a plurality of pipes 29 which may extend from the manifold 28. The number of pipes 29 may be limited to optimise the effect on the engine pressure. The greater the number of pipes 29 there are in the matrix 27, the greater the coolant pressure drop is across the engine 10. However a lower pressure may mean that the “spray” strength of the coolant 41 will be adversely affected. The matrix 27 may also be of a different design to that illustrated, which enables the coolant 41 to be delivered to the desired locations. In one embodiment the matrix 27 is cast, although it may be manufactured in any suitable manner from any suitable material.

The pipes 29 may have at least one aperture 30 extending through their sidewalls from the internal bores thereof which enable pressurised jets or a spray of liquid coolant 41 to be directed into the cylinder block 25 around the cylinders 12 and/or at the walls of the cylinders 12. Whilst a sufficient number of apertures 30 need to be provided to generate an effective spray of coolant 41, again the number of apertures 30 may be limited so as not to adversely affect the coolant pressure. The manifold 28 may also have one or more apertures 30 to assist in the distribution of the liquid coolant 41 onto the cylinder walls or other engine hot spots.

The fire deck 34 of the cylinder head 31 may be provided with a plurality of compound angled holes 35, each of which may cooperate with the bore of one of the pipes 29.

A liquid coolant reservoir 43 may be located in the cylinder block 25, which may comprise an oil cooler 44 for cooling the liquid coolant 41 before it passes into the matrix 27 via a suitable conduit 45 (see FIG. 6).

A coolant vapour conduit 36 may be fluidly connected to the cylinder head 31 and a scavenging pump 37 may be located in the conduit 36. Downstream from the water pump 37 may be a condenser 38. A return rump 39 may be provided in a return conduit 40 which may extend from the condenser 38 to the manifold 28 of the coolant delivery matrix 37 in the cylinder block 25.

The coolant delivery matrix 27 may be manufactured independently from the cylinder block 25 and cylinder head 31 and may be inserted, into the cylinder block 25 during construction of the engine 10.

INDUSTRIAL APPLICABILITY

When the engine 10 is started from cold, the coolant 41 in the cooling system 24 is in liquid phase and remains in liquid phase during engine warm up. Whilst the engine 10 is running the pumps 37, 39 operate to maintain a continuous flow of liquid coolant 41 to the cylinder block 25. Liquid coolant 41 is pumped into the manifold 28 of the coolant delivery matrix 27 in the cylinder block 25 and circulates round the manifold 28 and into the pipes 29. Some of the liquid coolant 41 is sprayed out of the apertures 30 in the manifold 23 and/or the pipes 29 (as shown by the dotted arrows in FIG. 4), the apertures being angled so that the jets spray on the walls of the cylinders 12. When the engine 10 has warmed up, the walls of the cylinders 12 will be of a temperature to cause the liquid coolant 41 to vaporise on contact to form coolant vapour 42, the evaporation process effecting cooling the walls of the cylinders 12.

Simultaneously jets of liquid coolant 41 may also pass through the multiple holes 35 in the fire deck 34. These holes 35 are angled to direct the flow of coolant 41 towards the mid deck 33 and the underside of the exhaust passage 21 (as shown by the straight arrows in FIG. 8) which are known hot spots of the engine 10. Some of the liquid coolant 41 vaporises on contact with the mid deck 33 and exhaust passage 21, whilst some of the liquid coolant 41 sprays down onto the fire deck 34, where further vaporisation occurs. The liquid coolant 41 is targeted at the known hot spots in the engine 10, which may be the small gaps between the valves and ports.

The coolant vapour 42 is drawn from the cylinder block 25 and cylinder head 31 as a result of suction created by the pump 37. Some of the coolant vapour 42 (shown by the curly arrows in FIG. 8) passes into the upper section of the cylinder head 31 via the gaps around the fuel injectors 14, where it passes into the coolant vapour conduit 36. Coolant vapour 42 from below the fire deck 34 passes into the coolant vapour conduit 36 from another collection point. The coolant vapour 42 is then directed through the condenser 33 and is condensed to its liquid phase to form liquid coolant 41. The liquid, coolant 41 is recirculated back to the cylinder block 25 by means of the return pump 39, where the aforementioned process repeats.

The cooling system 10 thus provides a continuous process of introduction of jets or sprays of coolant liquid 41 into the cylinder block 25 and cylinder head 31. These jets or sprays are directed at known hot spots therein and the resulting coolant vapour 42 is extracted. The sprayed coolant, liquid 41 may be specifically targeted at areas of the engine for specific cooling requirements.

As the coolant, delivery matrix 27 may be manufactured separately from the engine 10, this potentially reduces manufacturing costs and complexity. 

1. A cooling system for an internal combustion engine, the cooling system having a coolant delivery matrix configured for location in a cylinder block of the engine, said matrix comprising: a manifold; and a plurality of pipes extending from said manifold, wherein said matrix is configured to locate around at least one cylinder in the cylinder block, and each of the plurality of pipes has at least one aperture being directed to spray liquid coolant at a wall of the at least one cylinder.
 2. The cooling system of claim 1, further including: a supply pump fluidly connected to supply liquid coolant under pressure to the coolant delivery matrix; an extraction pump adapted to extract vaporised coolant from an the engine housing of the engine; and a condenser fluidly connected upstream to the extraction pump and downstream to the supply pump.
 3. The cooling system of claim 2, wherein: the at least one cylinder in the cylinder block includes a cylinder head attached to the cylinder block; and the at least one aperture is directed to spray the liquid coolant at one or more of the cylinder block and cylinder head.
 4. The cooling system of claim 3, wherein the manifold includes at least one manifold aperture being directed to spray the liquid coolant at the wall of the at least one cylinder.
 5. The cooling system of claim 3, wherein the cylinder head includes a fire deck in which a plurality of openings are provided, the plurality of openings cooperating with one or more open ends of the pipes to provide a passageway for the liquid coolant to be sprayed into the cylinder head.
 6. The cooling system of claim 5, wherein the plurality of openings of the fire deck are directed at one or more of a mid deck of the cylinder block and an exhaust conduit extending from the cylinder head.
 7. The cooling system of claim 6, wherein the engine includes a plurality of fuel injectors arranged to inject fuel into the at least one cylinder, and each of said fuel injectors extends through an aperture in the mid deck with a gap between the fuel injector and the mid deck providing a passageway for vaporised coolant to pass into an upper section of the cylinder head.
 8. A method of cooling an internal combustion engine, comprising: providing liquid coolant to a coolant delivery matrix under pressure wherein the matrix includes a manifold and a plurality of pipes extending from the manifold, and the matrix is configured to locate around at least one cylinder in a cylinder block of the engine; spraying a plurality of jets of the liquid coolant onto one or more selected parts of the engine; extracting vaporised coolant from the engine block; condensing the vaporised coolant into liquid coolant; and recirculating the condensed liquid coolant to the coolant delivery matrix.
 9. The method of claim 8, wherein the internal combustion engine includes a cylinder head attached to the cylinder block, and spraying the plurality of jets includes directing at least a portion of the liquid coolant to at least one of the cylinder block and the cylinder head.
 10. A method of manufacturing an internal combustion engine having a cooling delivery matrix, comprising: manufacturing the coolant delivery matrix, the matrix including a manifold and a plurality of pipes extending from the manifold, wherein each of the plurality of pipes has at least one aperture; manufacturing a cylinder block having at least one cylinder; positioning the coolant delivery matrix within the cylinder block so that the at least one aperture is directed to spray liquid coolant at one or more of the cylinder block and a cylinder head attachable to the cylinder block; and attaching the cylinder head to the cylinder block.
 11. The method of claim 8, wherein spraying the plurality of jets of the liquid coolant includes spraying, by at least one aperture of each of the plurality of pipes, the plurality of jets of the liquid coolant.
 12. The method of claim 8, wherein spraying the plurality of jets of the liquid coolant includes spraying, by at least one manifold aperture of the manifold, the plurality of jets of the liquid coolant.
 13. The method of claim 8, wherein spraying the plurality of jets of the liquid coolant includes directing a portion of the liquid coolant onto a wall of the at least one cylinder.
 14. The method of claim 9, wherein the cylinder head includes a fire deck in which are provided a plurality of openings, and spraying the plurality of jets of the liquid coolant further includes spraying the plurality of jets of the liquid coolant through a passageway provided by the plurality of openings.
 15. The method of claim 14, wherein spraying the plurality of jets of the liquid coolant through the passageway includes directing the liquid coolant into the cylinder head.
 16. The method of claim 14, wherein spraying the plurality of jets of the liquid coolant through the passageway includes directing the liquid coolant at one or more of a mid deck of the cylinder block and an exhaust conduit extending from the cylinder head.
 17. The method of claim 10, wherein: manufacturing the coolant delivery matrix further includes manufacturing the manifold to include at least one manifold aperture; and positioning the coolant delivery matrix further includes positioning the coolant delivery matrix within the cylinder block so that the at least one manifold aperture is directed to spray liquid coolant at one or more of the cylinder block and the cylinder head.
 18. The method of claim 10, wherein the cylinder head includes a fire deck in which are provided a plurality of openings, and attaching the cylinder head includes attaching the cylinder head to the cylinder block such that the plurality of openings provide a passageway for the liquid coolant to be sprayed into the cylinder head.
 19. The method of claim 19, wherein attaching the cylinder head further includes attaching the cylinder head to the cylinder block such that the plurality of openings of the fire deck are directed at one or more of a mid deck of the cylinder block and an exhaust conduit extending from the cylinder head.
 20. The method of claim 10, further comprising: manufacturing a plurality of fuel injectors; and arranging the plurality of fuel injectors to inject fuel into the at least one cylinder. 